1. Field of the Invention
The present invention relates to an information processing apparatus, a method of controlling printing, and a computer-readable storage medium.
2. Description of the Related Art
In the field of commercial printing, the orders for higher-value added small lot jobs are increased in number and the delivery times of such jobs is increasingly shortened. Accordingly, in addition to offset printers and post-processors in related art, print-on-demand (hereinafter referred to as POD) printers, which are digital printers, are actively introduced for variable data printing (hereinafter referred to as VDP).
In the initial VDP, VDP jobs are discriminated from offset printing jobs. The VDP jobs are processed by the POD printers whereas the offset printing jobs for mass printing of fixed data are processed by the offset printers.
Processing of mixed jobs by using both the POD printers and the offset printers is demanded in recent years, instead of the separate use of the VDP jobs and the offset printing jobs. Combinations of offset printers, offline post-processors, bookbinders, and POD devices are used for the mixed jobs because of the costs and processing times of the jobs.
Collation printing in which outputs are normally sorted on a record-by-record basis is performed in the VDP using the POD printers in the related art. In contrast, external collators are used in the offset printing to sort multiple quires.
In the processing of the mixed jobs from both the POD printers and the offset printers, it is necessary to merge printed sheets output from the respective printers. However, it is not easy to merge the printed sheets of the mixed jobs when the printed sheets are output in different output orders in the POD printers and the offset printers.
It is very important to prevent erratic pagination and missing pages in the VDP. This is because many VDP jobs are closely associated with information about customers and it is likely to disclose inappropriate information to the customers when the erratic pagination and/or the missing pages occur. In other words, it is necessary for commercial printers that deal with the VDP jobs to reliably detect and prevent the erratic pagination and the missing pages of the printed sheets because the presence of the erratic pagination and/or the missing pages may cause disclosure of information concerning the privacy of the customers. However, in the case of the collation printing using only the POD printers, any error affecting the privacy of customers does not occur.
The mechanical structures of the sheet conveying units in collators are improved in the collation in, for example, the offset printing in the related art in order to prevent the erratic pagination and the missing pages. In addition, image recognition technologies are improved to detect the erratic pagination that is not resolved only by the mechanical improvement.
In order to overcome the limitation of the image recognition to extract characteristics of prints, Japanese Patent Publication No. 5-5680 discloses a method of printing marking on quires and recognizing the markings.
Such a recognition method is effective for removing defective sheets when a large number of the same prints are output. When the number of the output prints becomes short as the result of the removal of the defective sheets, it is sufficient to simply reprint the same prints by the shortfall.
In the VDP in the related art, the printed sheets are output in the order similar to the order in which the printed sheets are output on a record-by-record basis from a variable database. The output on a record-by-record basis is also called the output on a set-by-set basis. Accordingly, the collating process becomes complicated when the printed sheets in the VDP are merged with the printed sheets output on a quire-by-quire basis in the offset printing.
In addition, when the printed sheets in the VDP are output on a page-by-page basis, the collation is performed also to the pages of the VDP jobs as the post-processing. In the case of the VDP in which the collation of the printed sheets is not performed, it is necessary to reliably detect and prevent the erratic pagination and the missing pages so that no error occurs in the content of each set and the binding result, as described above.
In the output of a large number of the same prints in the related art, even if double feeding occurs, removal of only the sets in which the double feeding occurs causes no problem in the remaining sets. However, in the VDP jobs, if the printed sheets become out of order as the result of the double feeding, all the subsequent sets are affected by the out-of-order. Accordingly, the method of detecting the erratic pagination by using markings, which is used when a large number of the same prints are output and which is disclosed in, for example, Japanese Patent Publication No. 5-5680, is not disadvantageously effective for the VDP jobs.
Furthermore, even if the erratic pagination can be detected, it is necessary to reprint all the VDP jobs because the double feeding has the effect on the remaining sets. Consequently, the cost in failure cases may be increased when the VDP jobs are mixed with the offset printing jobs.
The present invention is provided to facilitate confirmation of whether the printed sheets are correctly sorted in all the records in the VDP (assurance of output results in the VDP) and to realize the mixing of the VDP jobs with the offset printing jobs.